The present invention relates to a quick connector including a male part and a female part that couple together merely by inserting one into the other.
In pressurized fluid circuits that include quick connectors, it is desirable, or even required, to implement positive latching means for the connection. Poorly-established connection is firstly a source of leakage and secondly runs the risk of coming uncoupled, where the least-harmful consequence is to prevent operation of the machine that includes the pressurized fluid circuit, but that can also give rise to an accident if the machine is a vehicle (no pressure in a hydraulic brake circuit, fuel leaking into the engine compartment giving rise to fire).
Numerous devices exist for latching the male element in the female element of a quick connector. Substantially all of them operate on the same principle, implementing identical general means that consist in a keying member that is interposed between a radial surface of the endpiece (a groove or a collar) and a radial surface of the female element (likewise a groove or a collar). The keying member may be inserted manually or it may be held in its latching position by a resilient return member, with it being possible to place it in a retracted position against the effect thereof (either by moving it or by deforming it) when inserting the endpiece.
In a particularly simple embodiment of such a device, as shown in document FR 2 705 430, the latch is constituted by a ring mounted to slide radially in a housing formed in the female part of the connector between a rest, first position for latching, in which position it is off-center relative to the axis of the bore of the female part, and a retracted, second position for unlatching where it is substantially coaxial with the bore.
A resilient member constituted by two tongues made integrally with the ring is interposed between the ring and the female part and urges the ring towards its first position after the collar has passed through.
It is found that the above latching technique does not provide sufficient guarantee that the male part has been properly pushed home into the female part. The male part might be pushed only sufficiently to cause the collar to force the ring to move against the return spring, but not enough to ensure that the collar has gone beyond the ring, thereby preventing the ring from returning to its latching position behind the collar under the effect of the resilient tongues. That situation need not be immediately obvious to the operator, who might think that the connection has been made properly.
Documents EP0505930, EP0846907, FR2705431, and U.S. Pat. No. 6,145,886 disclose connectors having latching indicators that demonstrate that the connector has been properly latched, the latching indicator being located downstream from the latching member so as to be operated by a collar of the male part after the collar has gone beyond the latching member. In the connectors shown in those documents, the female part has special openings to allow the indicator to co-operate with the collar of the male part during insertion thereof, thereby weakening the female part and complicating fabrication.
In document EP 0 992 729, the indicator is likewise located axially offset from the latching member, but upstream from the latching member at the end of the female part. The indicator is driven not by the collar of the male part, but by an accessory entrained by the male part while it is being inserted in the female part, making that type of connector more complex.